When I next run, what is it?

Okay, as those in my group should know. I've been trying to figure out what I run next. (I'm not planning on being next, but know I should take a turn this year.)

I had a grand idea, but realized I was being too author-y. I kept shifting closer to a game and lost it all.

I need a setting, a story/plot...
Pretty much everything.

I'm not overly worried about the character's stats, for whatever system it is. But I lean GURPS, or if more action then D6. The D20s have all the wrong assumptions/constraints for me to run the game.

I really want to have a campaign world that I can run games in again and again. Where actions in one campaign shape the world for the next. Where I can tell the normal players "We're playing in /this/ world." Or even, I can say "I got an idea to run" and they make the true assumption it is that world.

So, what do I want? I want a fun and usable contradiction. I want a mystery that the players can interact with. (Above grand idea started with an impossible mystery, the 4 people who knew the answer didn't think it was important enough to write down, and died in a week. Effects only, no clues, no answers; no fun.)

I'd prefer magic over psionics, but will take a no supernatural option if necessary to prevent that from breaking my world.
Guns are boring, unless you're limited to about 20 shots each time you leave town, and then do other things to make guns special.

If I can make it, a magic & starships would be cool.

Another problem I have, is that I feel to create the game I want, I have removed everything of interest to the players.

I also need some good multi-protagonist fiction to make adventures in the world.

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The 3 ideas at the top of my mind right now are:
1. Star Wars - I can go though many WEG books, and I've read more of the novels than the others in our current group, but I'm not feeling it.
2. Old West / Wild West - 2 problems, one is "single protagonist" the other is no supernatural for one of the players
3. Age of Sail - but our prior "pirate" campaigns haven't gone well.

From the sound of it i think you need to run a detective/mystery game! I would run it as a super natural game where the charaters are all normals or half breeds that can see the super natural world around them. Id give them acsess to some guns and magic but would put the time line around the 1800's and put them in a city like london or france. Then makie all of there charaters fall into the plot some way or anouther by being involved with a crim ither from the supernaturals to the humans or vise versa. have this crime stir up the locals on both sides. You could even tie it into accual famos cases like jack the ripper or some such. And scine the charatures are all on the border between the human world and the supernatural world it becomes there mission to solve the case and to set the balance right. Ect ect. you can always come back to a setting like that because you can just make up more crimes and storys.


Thats my idea anyways.